A method of determining the out-of-balance effects on driven wheels of a motor vehicle and apparatus for supplying direct current to a device for measuring out-of-balance arranged on the motor vehicle.
The invention relates to a method of determining the out-of-balance effects on driven wheels of a motor vehicle using a device for measuring out-of-balance including oscillation converters and reference-mark scanning devices, and to an apparatus for supplying d.c. voltage to an out-of-balance measuring device, including drivers, oscillation converters and reference-mark scanning equipment, arranged on the motor vehicle.
An out-of-balance measuring device with oscillation converters and reference-mark scanning equipment has become known through a brochure of Messrs. Hofmann "Neue Qualitats-dimensionen under Rationalisierungswirkung durch Infra-rot abtastung finishbalancer lpi" dated February 1984. In this case, the electrical supply of the out-of-balance measuring instrument and of the associated auxiliary equipment is effected by means of alternating current. Apart from the limited usefulness of such a device, because of its dependence on the alternating-current supply, there is also the danger that dangerous potential differences may occur between the vehicle chassis, mounted in an insulated manner through the motor vehicle wheels, and the person operating the out-of-balance measuring equipment, which endanger the life of the operator. This also applies in particular when wheels of lorry and trailer combinations or articulated buses have to be balanced in the open air regardless of the weather. Independently of these dangers, because of the extended area--motor vehicle, lorry, articulated bus--of such a measuring arrangement, induction loops will also form and influence the measurement result, for example producing fluctuations in the indication, or even falsifying it--false measurement result. In addition, with the balancing device thus known, including the auxiliary equipment, it is necessary to align the motor vehicle to be examined with the measuring equipment, particularly for the purpose of scanning the marks provided on the motor-vehicle wheel. For this purpose, it is necessary to carry out several test runs with regard to the recognition of the markings on the wheels, which is not only expensive but also pollutes the environment as a result of the increased amount of exhaust gases expelled. In addition, with remote control for measuring the unbalance of both driving wheels, a differential speed monitoring must be continuously effected from the driver's seat in order to avoid overloading of the differential gear.